Taxa may commemorate personal names or surnames such as Alice Eastwood's Daisy, Virginia's Warbler, and Wilson's Honeycreeper. These names are treated as latinized possessive nouns (Alice's = aliciae, Wilson's = wilsoni). The classical accent may be determined by the Latin form of the name. If Wilson were latinized as Wilsonius the pronunciation of wilsoni would be "wil-SO-nye." If Wilson were latinized as Wilsonus, the pronunciation of wilsoni would be "WIL-so-nye." Archival records indicate inconsistency in latinization of names, so some flexibility exists in pronunciation, and there is precedent in both classical and modern Latin for conservation. Thus "WIL-so-nye" (Rule 2c ) is preferable to "wil-SO-ni," whereas andersoni is best treated as "an-der-SO-ni" rather than "an-DER-so-ni."

adrianus wrote:The Coues Check List of North American Birds, with a Dictionary of the Etymology, Orthography, and Orthoepy of the Scientific Names. 2nd edn. Boston: 1882.http://www.archive.org/details/cihm_06202

The author of this work seems in most cases to propose an accentuation of the Latin words in such a way that the accent of the word in the original language is retained. In itself, this is not unreasonable, but he draws it too far, I think. This principle of his is explicit in the case of names of three syllables (p. 21): "Modern proper names of three syllables with the accent on the first, keep it there after addition of the i of the genitive case; as, aud'uboni, rich'ardsoni." Thus it is not surprising that we also find hăm'-mŏnd-ī (Hammond), strĭck'-lănd-ī (Strickland), and lĭn'-cŏl-nī (Lincoln). But accentuations such as these, which blatantly breaks the normal accentuation rules of Latin, makes me very wary. While this may have been or even be the current practice when pronouncing these scientific names in an English context, I'm very sceptical of introducing this pattern into the Latin language proper. Of course, accentuations such as frănk'-lĭn-ī (Franklin), hŭt'-tŏn-ī (Hutton), nĕl'-sŏn-ī (Nelson), etc. do not break any rule, but for the previously mentioned reason I don't think this particular book is a very good authority when it comes to accentuating the names in a purely Latin context (i.e. when using Latin as an actual language in its own right, rather than merely as a scientific code).

Taxa may commemorate personal names or surnames such as Alice Eastwood's Daisy, Virginia's Warbler, and Wilson's Honeycreeper. These names are treated as latinized possessive nouns (Alice's = aliciae, Wilson's = wilsoni). The classical accent may be determined by the Latin form of the name. If Wilson were latinized as Wilsonius the pronunciation of wilsoni would be "wil-SO-nye." If Wilson were latinized as Wilsonus, the pronunciation of wilsoni would be "WIL-so-nye." Archival records indicate inconsistency in latinization of names, so some flexibility exists in pronunciation, and there is precedent in both classical and modern Latin for conservation. Thus "WIL-so-nye" (Rule 2c ) is preferable to "wil-SO-ni," whereas andersoni is best treated as "an-der-SO-ni" rather than "an-DER-so-ni."

This is also interesting. Regarding the last remark, I suppose that "an-der-SO-ni" would be preferable to "an-DER-so-ni" because the conflict with the original accentuation "AN-der-son" is diminished by moving the stress two syllables rather than one (and so enabling a secondary stress on the first syllable, if you wish). At least that was the purely subjective reason why I preferred "e-ver-SO-nus" instead of "e-VER-so-nus".

But going back to Wilson, which seems sufficiently analogous to Dodgson, you are of course right that this source clearly advocates "Wilsŏnus", and relying on this alone, I would have been mistaken with "Dodgsōnus". However, the usage of poets paints a very different image. Searching for "Wilsonus" in Google books reveals a dozen verses, all of which indicates "Wilsōnus". (In case you wonder, these are not cherry-picked; I went through all the Google hits, and was surprised to not find any counterexamples):

(I can give links to these hits, if you wish, but I have to do it in a separate post. The forum did not allow me to post more than 10 links in one post.)

So it seems that the usage varied, either over time or in different domains. Perhaps Dodgson himself would have gone for "Dodgsŏnus", seeing that he was closer in time to the authors of the handbooks for accentuations of scientific names; I don't know. But I don't think the 16th century poets, who were writing in a much more living tradition, should be so quickly disregarded. Considering also that "archival records indicate inconsistency in latinization of names, so some flexibility exists in pronunciation", it would be unfair to call "Dodgsōnus" an error, I think.

Links to the sources for the verses. (Some of these may give a different view than I see; Google gives different results depending on your country. Here in Sweden I can see most of these hits only in the snippet view.)

George Don, A general history of the dichlamydeous plants, comprising complete descriptions of the different orders......the scientific names accentuated...the whole arranged according to the natural system (London, 1831) (http://www.archive.org/details/mobot31753000734738) prefers typically -ius names, to give "Adanso'nii" "Richardso'nii" "Nelso'nii" "Commerso'nii", no doubt because it sounds better.